Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 1721
'A'isha reported that the Apostle of Allah (may peace be upon him) listened to the recitation of the Qur'an by a man in the mosque. Thereupon he said: May Allah have mercy upon him; be reminded me of the verse which I had been made to forget.